I'm guessing this is telling me the switch is looking for a Master in a stack that it was once part of?

This error is stopping me from resetting the config as the switch never fully initialises.

I can get into the bootloader and have tried setting the image to null, but the above error keeps resetting the switch before I get a recovery logon prompt.

I've seen other articles that say updating the firmware through TFTP will fix this, but when I enter the serial number on the support page, I'm told no downloads are available for the switch.

I guess this is because it's out of maint, which is fair enough and I wouldn't expect to have access to the latest version of the firmware, but I would hope I can download the same version the switch is already running.